Telephone-exchange system.



PATENTED NOV. 13, 1906.

H. G. WEBSTER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED D50 16. 1904.

UNITED STATES PATENT OFFICE.

HARRY G. W EBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO MILO G. KELLOGG, OF CHICAGO, ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

tral source located at the exchange and-in' which the cut-off relay which controls-the normal connections of the line is actuated by current which flows over a portion of, the talking-circuit when connection is made with the spring-jack or switching-terminal. The object of my invention is to provide an improved organization of circuits and apparatus for systems of this class in which the source or sources of current which serve to energize the substation-transmitters may be associated with the cord connecting apparatus only and may be distinct and separate from that source associated with and fur-' nishing current for the actuation of the a paratus which is individual to the various ine-' circuits, Among the advantages of such an arrangement may be included the possibility of using a comparatively low voltage source in normal connection with the lines, thus aining a reduction in leakage and electroytic action, a decrease in the volume of current set up in the line when a subscriber initiates a call, and a consequent reduction in the click which is heard in his receiver upon the insertion of a connecting-plug. A second advantage is that with my system it is possible to associate with the cord-circuit or with certain of the cord-circuits a source of current adapted for the particular .group of lines with which the cord-circuits are to make connection or for any special purpose. For instance, where certain cords-are used for connecting subscribers lines for long-distance or f toll service it is possible with my system to provide such cord-circuits with a source of current of greater strength than that which is necessary or desirable for normal transmission or for the normal operation of the cutofi rela s and signal-controlling magnets individua to the lines. Other ad Specification of Letters Patent.

Application filed December 16, 1904. Serial No. 237.147.

Patented Nov. 13, 1906.

vantages of my im roved system will be apparent from the following description In accordance with a preferred form of my invention I provide spring-jacks or switching-terminals at the central exchange, each having two contact-pieces corresponding to the two line-limbs. One of these contactpieces may be permanently associated with the line, and the other contact-piece, which is also utilized as a testin terminal, is normally disconnected from t ie individual linelimb and includes in its circuit the winding of a cut-off relay, the relay serving when energized to destroy the substation control ofthe calling-signal and to brin the said contact into direct connection with the line-limb. Cord connecting apparatus is provided whereby the insertion of a connectingplug into a s ring-jack closes the circuit of this relay tirough one of the talking-strands of the cord-circuit, and this circuit may also i11- clude the relay or impedance associated with a cord-circuit which serves to control the flow of transmission-current from the corresponding side of the talking-circuit. The central battery, which is normally connected with the line and which serves to energize the magnet controlling the display of a callingsignal, also serves to furnish current for the operation of the cut-off relay, and the resistance ofi the cut-off relay and the voltage of what may be called the linebattery are so proportioned that upon the insertion of a connecting-plug the current which flows from this battery to the cut-off relay'will be entirely confined to the circuit which is compieted through the cord-strand. The resist- ;ance of the cord-circuit apparatus andthe yoltageof what may be called the transmission-battery associated with the cordcircuit are such that currentfrom this latter battery is confined to the talking-strands of the cord-circuit and the two limbs of the line and does not at any time flow through the winding of the cut-off relay. One arrange ment of cord connecting apparatus which may be used with my invention prov des a relay of com a'ratively low res1stance associated with t e sleeve-strand of the cord-cir- IOO cuit and the corresponding contact piece" of the connecting-plug and with the ground or ofiice return, which serves when energized to complete a local circuit of the supervisory signal associated with the corresponding plug tion of the hook-switch.

and provides a second relay of comparatively low resistance interposed between the tipstrand and the active terminal of the transmission-battery, which is controlled by current flowing through the line-limbs and substation apparatus and serves when energized to open the circuit of the supervisory signal, and thus bring its display under the control of the subscriber. I have found in practice that in such an arrangement as I have indicated the cut-off relay may have a resistance of eight hundred ohms, the two cord-relays a resistance of one hundred ohms each, the transmission-battery being of twenty-four volts, and the linebattery having somewhat more than half this voltage (as fourteen or sixteen volts) with satisfactory results, although I do not limit myself to the specific proportions between these resistances and voltages.

My invention will be further understood from the accompanying drawing, which illustrates diagrammatically two complete linecircuits and appropriate cord connecting aparatus organized in accordance with a pre erred form of my invention.

Like characters refer to corresponding parts in the drawing.

The subscribers apparatus (shown at A) is represented as consisting of a telephone hookswitch h, a signal-bell b, condenser 'c, receiver 1, and transmitter t, the bell and condenser being in ermanent bridge of the two linelimbs an the circuit being closed through the receiver and transmitter upon the eleva- Although I have shown but one arrangement, it will be understood by those skilled in the art that .various other arrangements of the subscribers apparatus may be used, and I do not confine myself to the particular arrangement illustrated. Under normal conditions the receiver hangs upon its hook-switch, maintaining its upper contact open, and the condenser c prevents a normal flow of current from line-battery C at the central office over th line-limbs. When the subscriber removes his telephone from its hook, thus closing the upper contact of hookswitch it and establishing a relatively low-resistance path for the flow of current through the transmitter t and receiver 1", relay 4 at the central office will be operated by the flow of current from said battery C through the winding of relay 4, anvil 8, and armature 6, the two limbs of the line, and throu h armature 7 and anvil 9 to the return si e of the battery. This flow of current through relay 4 causes its energization and the consequent illumination of callin -lamp 5. Each subscribers'line is provi ed with one or more spring-jacks j, each having contact-pieces 11 and 12 for limbs 1 and 2 of the line, respectively, contact-piece 11 being directly connected with limb 1 and contact-piece 12,

which serves as a testing-terminal, being con- "nected throug'h'the winding of cut-off relay 3 to the active side of battery C. i The illumination of signal-lamp 5 indicating to the operator that the subscriber has removed his receiver from its hook for the purpose of making a call, she inserts the answering-plug P into a springjack 3' corresponding to the callingsignal, thus causing contact-piece 13 of the plug to engage contact-piece 1 1 of the spring jack and contact-piece 14 of the plu to engage contact-piece 12 of the spring-jac Current will now flow from battery C through the winding of relay 3, conductor 31, plug and jack contact 12-14:, strand 17 of the cord, and the winding of relay 21 to the return side of the battery. The current through this circuit causes the energization of relay 3, and the actuation of armature 6 interrupts the circuit through limb I at anvil 8, while the the actuation of armature 7 interrupts the circuit through limb 2 at anvil 9, and its engagement with anvil 10 connects this limb directly with conductor 31 and the circuit previously traced through relay 21. Relay 21 is also energized, closing the local circuit of the supervisory lamp 23 at its contact. Current will now flow from batteryD through relay 19, strand 15, plug and jackcontact 131 1, limbs 1 and 2 of the line, conductor'31, plug and jack contact 12-14, and thence through strand 17, and relay 21 to the return 9 side 0 the battery D. This current serves to energize the substation transmitter and also energizes relay 19, causing it to open the local circuit of supervisory lamp 23 and preventing its illumination as long as the circuit is complete through the substation apparatus. After being informed with what line. connection is desired, in this case that of subscriber B, the operator tests in the usual manner by touching the tip of her calling plug O tothe contactpiece 12 of a jack associated with that line. It will be seen that under normal conditions no noise will be heard in the receiver of the operators set S at this time, for the reason that contact-piece13 of the callingplug is normally connected through the common test-relay 28 to the active side of battery C, with which contact-piece 12 is permanently connect-ed. If, however, a connecting-plug is in a spring-jack of the line tested, this contact-piece has its circuit completed to the return side of the battery throu 'h the associated cord-relay, and its electrical condition is thereby altered. In making the busy test under this condition current will flow-from battery 0 through relay 28, anvil 26, and armature 25 of the relay 22 associated With'the testing-cord, and thence through strand 16 and contact-piece 13 to the return side of the battery, causing the energization of relay 28. The engagement of armature 29 of this relay with its anvil or front contact short-circuits the condenser d of the operator's circuit, thus causing a flow of current through the local winding of-her induction-coil and producing the click which indicates that the line 1s busy.

Upon the insertion of the actuation of the ringing-key 3 is energized by current from battery C flowing through its winding, conductor 31, plug and jack contact 14-12, and thence through strand 18 to the office return shown in association with generator G. The circuit of the calling-generator G is at this time completed through resistance-lamp 30, strands 1618 of the cord-circuit, contacts 13l1 and 14-12 of the plug and jack, and limbs l and 2 of the line. Upon the restoration of the ringingkey relays 3 and 22 are energized by current from battery C flowing through the winding of relay 3, conductor 31, lug and jack contact 1412, strand 18, an the winding of re lay 22 to the return side of the battery. The energization of relay 3 serves to control the normal connections of limbs 1 and 2, as re viously described, and the energization 0 relay 22 closes the circuit of supervisory lamp 24, while the actuation of its armature 25 disconnectsthe common test-relay 28 at anvil 26 and engaging anvil 27 completes the circuit of strand 16 to relay'20 and condenser d. As soon as subscriber B answers current lug O and the i from battery E will fiow through relay 2O current for tal over a circuit similar to that previously traced for battery D and relay 19, thereby extin guishing supervisory lamp 24 and energizing the substation-transmitter. The lines of the two subscribers are now inductively united for conversation by'qneans of condenser d, in terposed between strands 15 and 16, and condenser d, inter osed between strands 17 and 18. When eit ler subscriber hangs up his receiver, it causes the illumination of the corresponding supervisory lamp, and the illumination of bothlam s constitutes the customary disconnect-sigma lay 3 is under all conditions energized by current from battery 0 and that this battery need not be adapted to and does not furnish ng purposes; also, that the current from battery D or E, which serves to ener ize the substationtransmitters, does not 50w throu h the winding of relay '3 and that byproper yproportioning the various resistances the batteries D orE as well as battar ;1 C, may be given any voltage value desire It will be understood that the various grounds shown in the drawing represent the return side of the several batteries or the central-office ground; also, that while separate bateries D and E have been indicated these batteries may be one and the same. It will also be understood by those skilled in the art that various modifications of my invention may be made without departing from its s irit, and I therefore do not limit myself to the precise structure, illustrated and described; but

evers g g relay' I claim 1. The combination with a tclephone-linc, and a connection-terminal therefor, of a signal-controlling electroma net normally connected with said line, a rc lay for disconnecting said electromagnet from the line, a source of current associated with circuit terminating in a connecting-plug and adapted to be placed in conductive relation with the line, a source of electricity asso-- ciated with the cord-circuit and adapted to be placed in metallic circuit of the line, and means for closing the circuit of said first-mentioned source through said relay when.connection is made with the line, said relay-circuit including a talking-strand of the cordcircuit, a main terminal of the connectingplu a line-contact and'a portion of the tall ingimb of the telephone-line with suitable return, substantially as described.

2. The combination with a telephone-line, of line-contacts therefor, a signal-controlling electromagnet normally connected therewith, a relay for disconnecting said electromagnet It will be seen that the re from the line, a source of current associated with said relay, a cord-circuit terminating in a connecting-plug, a second source for supplying current for talking purposes, connected in bridge of said cord-circuit, and'means for closing a circuit of said first-mentioned source through said relay, said circuit includ ing a talking-strand of the cor'd circuit, a main terminal of the connecting-plug, and a line-contact of the telephone-line, substantially as described.

3. The combination with a telepl1oneline, of contacts therefor, a signal-controlling electromagnet normally connected therewith, a relay for disconnecting said electromagnet from the line, a source of current associated with said relay, a cord-circuit termiiiiating in a connecting-plug, a second source of current ings of said relay and said first-mentioned source of current being adapted to be included in shunt of a portion of one of the limbs of the telephone-line and said second source of current, and means for closing a circuit through said relay including a talkin strand of the cord-circuit, a terminal of the co meeting-plug, a line-contact of the telep one-line and the portion of a talklng-llmb of the telephone-line extending between the said line-contact and the winding of said relay, substantially as described.

4. The combination with a telephone-line, of a connection-terminal at the central station, a signal-controlling electromagnet normally connected therewith, a relay for disconnecting said electromagnet from the line, a cord connector terminating in a connecting plug, a source of current associated with said relay, said source being adapted when said connecting-plug is inserted in the connectionterminal to send current over a circuit insaid relay, a cord- 1 associated with said cordci rcuit, the windcluding a talking-strand of said cord connector, a terminal of the connecting-plug, a

furnish current for talking purposes, and

means for closing the circuit of said firstmentioned source through said relay when connection is made with the line in response to the call, said relay-circuit including one of the main terminals of the connecting-plug and a line-contact of the telephone-line with suitable return, substantially as described.

6. The combination with a metallic telephone-line and a connection-terminal normally disconnected therefrom, of a relay for connecting said connection-terminal with the line, a source of current associated therewith, a cord-circuit terminating in a connecting-plug, a source of talking-current in bridge of said cord-circuit adapted to send current over the metallic circuit, and means for closin the circuit of said firstmentioned source thiough said relay when connection is made with the line, said relay-circuit including a talking-strandof the cordcircuit, a main terminal of the connectingplug, a line-contact and a portion of the talking-limb of the telephone-line, substantially as described.

7 The combination with a telephone-line and a connection-terminal normally disconnected therefrom, of" a relay for connecting said connection-terminal with the line, a source of current having its active pole nor mally connected to said terminal, a cordcircuit terminating in a connecting-plug, means for closin and maintaining a circuit of said source t rough said relay continuously during a connection and over a circuit including a talking-strand of the cord-circuit, a main terminal of the connecting-plug and a line-contact of the connection-terminal, and a second source for supplyin current for talking purposes, connected in bridge of said cord-circuit, substantially as described.

8. The combination with a tele hone-line and a connection-terminal norma ly disconnected therefrom, of a relay for connecting said connection-terminal with the line, a source of current associated with said relay, a cord-circuit terminating in a connecting-plug, a second source of current associated with said cord-circuit, said first-mentioned source I of current and the winding of said relay be ing adapted to be connected in shunt of a portion of one limb of the telephone-line and said second source of current, and means for sending current through said relay over a circuit including a talking-strand of the cord connector, a terminal of the connectinglug, a line-contact of the telephone-line an the portion of a talking-limb of the telephoneine extending between the line-contact and the winding of said relay, substantially as described.

9. The combination with a tele hone-line and a connection-terminal normally disconnected therefrom, of a relay for connecting said connection-terminal with the line, a source of current associated with said relay, said source and the winding of said relay being adapted to be connected in shunt of a portion of one limb of the telephone-line, a cord connector terminating in a connectingplug, a source of current connected between the strands of said cord connector adapted to furnish current for talking purposes, and means whereby the insertion of the connecting-plug into the connection-terminal sends current from said first-mentioned source over a circuit including a talking-strand of said cord connector, a terminal of the connectinglug, a line-contact of the telephone line, an the portion of a talking-limb of the telephone-line extending between said linec'ontact and said relay, substantially as described.

10. The combination with a telephoneline adapted to be included in a talking-circuit, of a signal-controlling electromagnct normally connected therewith, a connectionterminal normally disconnected from said line, a relay for disconnecting said electromagnet from the line and for connecting said connection'terminal with the line, a source of current associated with said relay, a second source of current ada ted to be connected in the metallic circuit 0 the line to furnishcurrent for talking purposes, and means for closing a circuit of said first-mentioned source through said relay over a portion of the talking-circuit when connection is made with the line, substantially as described.

11. The combination with a telephoneline, of a connection-terminal normally disconnected therefrom, a relay for connecting said connection-terminal with the line, a source of current associated with said relay, a separate source of current adapted to be connected in the metallic circuit for talking purposes, means for operating said relay from said first-mentioned source when connection is made with the line by current flowin over a path including a portion of the ta king-circuit, and means for sending a calling-current over the line of the called sub- I scrldi i "Ii'nd a35,eo2

Y same timemaintaining sfifi ilalfiy 'iii operative condition, sub stantially as described.

12. The combination with a tclephoncline,'of one of the talking contacts of a s ringjack associated with the said line, sai contact being normally disconnected. from the line, a plug, a cord-circuit, a battery asso c1 ated with the said circuit adapted to be 1ncluded in the metallic circuit of the line to furnish current for talking pur oses, a second source of current and a re ay operated from said second source of current over a portion of the talking-circuit to connect said contact with the line during such use, substantially as described.

13. The combination with a metallic telephone-line, of a talking contact forming a part of a connection-terminal for the line, said contact being normally disconnected therefrom, a central source of current associated with the line and adapted to be included in the metallic circuit of the line when a connection exists to furnish current to the substation-transmitters for talking purposes,

rent from said second source over a portion of the talking-circuit to connect the contact with the line when the line is in use, and testing apparatus to cooperate with said con tact to indicate the condition of the line, substantially as described.

14:. The combination with a telephoneline, of a test-terminal normally disconnected therefrom, a relay for connecting said tes tterminal with'the line, a source of current associated therewith, testing apparatus, a cordcircuit terminating in a connecting-plug, supervisory si naling apparatus associated with the cor circuit, a source of electricity also associated with the cord-circuit, means for closing the circuit of said last-mentioned 'source over the telephone-line to operate the said supervisory apparatus, and means for closing the circuit of said first-mentioned source through said relay when connection is made with the line, said relay-circuit including one of the main terminals of the connectin -plug and a line-contact of the telephoneine with suitable return, substantially as described.

15. The. combination with a telephoneline and a connection-terminal therefor, having a contact normally disconnected from the line, of a connectin -plug and cord-circuit to cooperate with said ine, a supervisory signalcontrolling magnet and a battery associated with said cord-circuit, a telephone-transmitter and a switch at the subscribers station, and means including a separate source of current controlled by the insertion of the plug into the ack for connecting said contact with the line by current flowing over a path including a portion of the talkingcurrent, whereby current is furnished to said transmitter and said magnet is placed under the control of the subscriber, substantially as described.

16. The combination with a metallic telephone-line adapted to be included in a talking-circuit, of a line-si nal and a cut-off relay for the line, a source 0 current for energizing said relay, a cord-circuit, a separate source of current associated with the cord-circuit adapted to furnish current for talking purposes, and means for closing circuit through said relay and said first-mentioned source over a portion of one side of the talking-circuit when connection is made with the line to render the line-signal inoperative, substantially as described.

17. The combination with a telephoneline and a cord-circuit adapted to beincluded in a talking-circuit, of a line-signal and a cutoff relay for the line, a source of current associated with said relay, means for closing circuit from said source through said relay over a portion of one side of the talking circuit, including a portion of the telephone-line and the cord-circuit, and a second source for supplying current for talking urposes, connected in bridge of said cor -circuit, substantially as described.

18. The combination with a tele honeline and a connection-terminal in the orm of a spring-jack, of a connecting-plug and a cord-circuit, a central source of current associated with said circuit to furnish current for talking purposes, supervisory signal apparatus associated with the cord-circuit and operated from said source of current, and a relay actuated'from a separate source of current by the insertion of said plug into, and its witl'idrawal from, said jack for controlling a connection of said jack with said line, said relay being actuated by current flowing over a portion of a strand of the cordcircuit, a ta king contact of the plug and jack and a portion of the telephone-line, substantially as described.

19. A telephone system comprisin a telephone-line, an electrically-actuated signal and a source of current associated with said line, a cord-circuit for making connection to said line, means for holding conversation over said line and cord-circuit, means normally under the control of the subscriber for displaying said signal by closing a circuit through said source of current, a relay for placing said signal beyond the control of the subscriber, a second source of current associated with the cord-circuit, and means under the control of the operator for energizing said relay and sup lying current for talking purposes by comp eting two parallel aths, one path includin an energizing-win ing of said relay and sai first-mentioned source of current and said second path including said second source of current and a portion of the telephone-line. I

20. A telephone system comprising a tele phone-line, an electrically-actuated signal and a source of current associated with said line, a cord-circuit for making connection to said line, means for holding conversation over said line and cord-circuit, means normally under the control of the subscriber for displayin said signal by closing a circuit throng said source of current, a relay for placing said signal beyond the control of the subscriber, a. second source of current associated with the cord-circuit, and means under the control of the operator .for energizing said relay and sup lying current for talking purposes by comp eting two parallel paths, one path including an energizing-winding of said relay and said first-mentioned source of current, and the second path includin said second source of current and portions 0 both telephone-line limbs.

21. A telephone system comprising a telephone-line, an electrically-actuate signal and a source of current associated With said line, a cord-circuit-for making connection to said line, means for holdingconversation over said line and cord-circuit; means normally under the control of the subscriber for dis laying said signal by closing a circuit throng said source of current, a relay for placing said signal beyond the control of the subscriber, a second source of current associated with the cord-circuit, and means under the control of the operator for ener izing said relay and supplying current for tssking purposes by completing two parallel paths, one path including an energizing-windingof said relay and said first-mentioned source of current, and the secondpath including said sec ond source of current, a strand of the cord circuit, and portions of both telephone-line limbs.

In witness whereof I hereunto subscribe my name this 10th day of December, A. D. 1904.

HARRY G. WEBSTER. 

